What is the primary characteristic of enzymes?

• A. They are consumed in chemical reactions
• B. They are highly specific and reusable
• C. They have a wide range of substrates
• D. They can function without cofactors

Answer: (B)

The primary characteristic of enzymes is that they are highly specific and reusable. Enzymes are biological catalysts that speed up chemical reactions by lowering the activation energy required for the reaction to occur. Each enzyme is tailored to interact with a specific substrate (the molecule it acts upon), leading to a precise biochemical reaction.

The specificity comes from the unique active site of the enzyme, which is shaped in such a way that only substrates with complementary shapes can bind effectively. This means that each enzyme will typically catalyze only one specific reaction or a group of closely related reactions, depending on the structure of the active site.

Additionally, enzymes are not consumed in the reactions they catalyze, which allows them to be reused multiple times. Therefore, once an enzyme has facilitated a reaction, it can return to its original state and catalyze additional reactions with new substrate molecules. This ability to be reused and their specificity makes enzymes incredibly efficient and vital for biological functions.